Fatal error: Uncaught TypeError: Return value of think\Container::setInstance() must be an instance of think\void, none returned in E:\phpstudy\PHPTutorial\WWW\law-firm_back\vendor\topthink\fr
amework\src\think\Container.php:86 Stack trace: #0 E:\phpstudy\PHPTutorial\WWW\law-firm_back\vendor\topthink\framework\src\think\App.php(167): think\Container::setInstance(object(think\App)) #1 E:\phpstudy\PHPTutorial\WWW\law-firm_back\public\index.php(18): think\App->__construct() #2 {main} thrown in E:\phpstudy\PHPTutorial\WWW\law-firm_back\vendor\topthink\framework\src\think\Container.php on line 86
